Device for adjusting the timing of an injection pump



Oct. 27, 1959 J. Hx-:lsER 2,910,696

DEVICE FOR ADJUSTING THE TIMING OF' AN INJECTION PUMP Filed Aug. 1e, 1957 /N VEA/TOR ua/0' eef' WJMQ FTTORNEV United States Patent C DEVICE FOR ADJUSTING THE TlMlNG F AN INJECTION PUMP Joachim Heiser, Stuttgart-Wangen, Germany, assignor to Robert Bosch G.m.b.lil., Stuttgart, Germany Application August 16, 1957, Serial No. 678,721 Claims priority, application Germany August 22, 1956 6 Claims. (Cl. 12S- 139) The present invention relates to internal combustion engines.

More particularly, the present invention relates to injection pumps ofinternal combustion engines and especially to structure for adjusting thte timing of an injection pump.

Although devices for yadjusting the timing of injection pumps are known at the present time, the known devices have several disadvantages in that they are relatively expensive and take up a considerable amount of space inasmuch as they include such devices as servo motors and mechanical transmissions cooperating therewith. Furthermore, the known devices do not provide the desired freedom of movement in the area where the structure is located.

One of the objects of the present invention is to provide a device which will adjust the timing of an injection pump in dependence upon the speed of an engine which includes the injection pump and which overcomes the above drawbacks by providing a structure which is relatively inexpensive and which requires a relatively small amount of space and provides the desired freedom of movement in the area where the structure is located.

A further object of the present invention is to provide a device of the above type which uses an overow valve to bring about the desired adjustment.

Another object of the present invention is to` provide a device of the above type which will in addition control the amount of `fuel delivered by the injection pump to the engine.

With the above objects in view, the present invention includes in a device for `adjusting the timing of an injection pump a movable adjusting means for adjusting the timing of the injection pump and a hydraulic moving means for moving the movable adjusting means to carry out the necessary adjustment, this hydraulic moving means responding to changes in the pressure of a liquid in the hydraulic moving means. An overflow valve means communicates with the hydraulic moving means and includes a movable valve member acted on by the liquid under pressure in the hydraulic moving means and movable to vary the pressure of this liquid so as to provide movement of the movable adjustable means when the valve member moves. A further means is provided for absorbing a portion of a centrifugal force and for moving the valve member of the overflow valve means when this portion of the centrifugal `force is absorbed so as to adjust the timing of the injection pump in response to the centrifugal force, the latter centrifugal force being provided by a means connected to the engine itself to be driven thereby at a speed proportional to the speed of the engine.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be bestvunderstood from the yfollowing description of specific 2,910,696 Patented Oct. 27, 1959 ICC . the essential parts of the adjusting structure of the present invention; and

Fig. 3 is a fragmentary partly sectional view of a different embodiment of an overflow valve from the embodiment of Fig. 2.

Referring to Fig. 1, the injection pump 1 is supplied with fuel by `a supply pump 2. which sucks fuel from the reservoir 3 through a suction conduit 4, and the pump 2 delivers the fuel under pressure through a discharge conduit 5 and through a filter 6 to the injection pump 1. A fuel conduit 7 communicates with and extends from the conduit 5 and this conduit 7 communicates with a co-ntrol device 8 as well as 'with a cylinder 9 of a hydraulic moving means. This hydraulic moving means includes in addition to the cylinder 9 a piston 10 which is slidable in the cylinder and which is acted upon at one side by a coil spring 11 and on the other side by the liquid under pressure which is derived through the conduit 7. The piston rod of the piston 10 is connected, as through a pin and slot connection, for example, to a two-armed lever 12 which in turn is operatively connected to a movable adjusting means 13 which adjusts the timing of the injection pump in response to axial movement of the movable adjusting means 13.

This movable adjusting means 13 has the construction shown in Fig. 1 according to which it is provided at its outer surface with an annular groove into which a free end portion of the lever 12 distant from the piston 10 extends, this lever 12 being pivotally supported intermediate its ends on a portion of a housing 17 on which the adjusting means 13 is located and into which the lever 12 extends in the manner shown in Figs. 1, the housing 17 being carried by the injection pump 1. The movable adjusting means 13 has a pair of coaxial openings formed with oppositely directed threads of large pitch, and a pair of shafts 14 and 15 have correspondingly threaded free end portions respectively extending through these openings and connected threadedly with the means 13. The pitch of the oppositely directed threads is large enough so that the shafts 14 and 15 can be turned in response to axial shifting of the element 13. The shaft 15 forms the drive shaft of the injection pump 1 and the shaft 14 is driven by the engine at a speed proportional to the speed of operation of the engine. When the means 13 is shifted axially the angular positions of the shafts 14 and 15 with respect to each other will change depending upon the extent of axial movement of the means 13 and as a result the timing of the injection pump with respect to the engine will be adjusted because of the change in the angular positions of the coaxial shafts 14 and 15 with respect to each other.

The shaft 14 xedly carries a sprocket wheel 18 which rotates With the shaft 14 and which cooperates with a sprocket chain 19 which drives the control means 8.

A conduit 20 communicates with the control means 8 and with the interior portion of cylinder 9 on the right side of the piston 10, as viewed in Fig. l, where the spring 11 is located, and this conduit 20 leads to the reservoir 3 so that fuel returns to the yreservoir 3 through the conduit 20.

A bar 21 extends to the right beyond the control means 8 from the interior thereof, as viewed in Fig. 1, and this bar 21 is supported for axial shifting movement and is pivotally connected to one end of a lever 23 which is pivotally supported intermediate its ends by a bracket fixed to the injection pump 1. The opposite end of the two-armed lever 23 is pivotally connected with an axially shiftable rod 24 which controls the amount of Yfuel supplied by the injection pump to the engine in a known way, so that when the bar 21 is axially shifted in a manner described below the amount of fuel supplied by Vthe injection pump will be adjusted.

As is apparent from Fig. 2, the control means 8 includes a housing 31 having a hollow chamber at its left end portion, as viewed in Fig. 2, and this hollow chamber communicates both with the conduit 7 and with the conduit Zti. The portion of the housing 31 which forms the right wall of this chamber is` provided with an opening which serves as a bearing for supporting a shaft 32 for rotational and axial shifting movement,

= this shaft 32 having a substantially pointed left free end portion, as viewed in Fig. 2. The shaft 32 extends to the right to a right end wall of the housing 31, as viewed in Fig. 2, and this right end wall also supports the shaft 32 for rotational and axial shifting movement, the elongated portion of the shaft 32 which is located to the right cf the ball members 37 shown in Fig. 2 being hollow, for a purpose described below. A cross pin 33 is fixed to and extends through the shaft 32 and this cross pin 33 is fixed to a turning means in the form of a sprocket wheel 34 which cooperates with the sprocket chain 19, so that the turning means 34 rotates the shaft 32 about its axis. The sprocket chain drive for rotating the shaft 3f. has sufficient play in its parts to permit the desired relatively small amount of axial shifting of the shaft 32, and it will be noted that the opening in the bottom wall of the housing 31 through which the sprocket chain 19 extends is large enough in an axial direction to give the desired axial movement of the parts without interfering with the chain 19. A control sleeve 36 has its inner cylindrical portion interposed between the turning means 34 and the shaft 32, this cylindrical portion of the controlsleeve 36 slidably engaging the shaft 32 which passes through the cylindrical portion and in addition the latter cylindrical portion of the sleeve 36 serves as a support for the sprocket wheel 34 which is xed to the shaft 32 by the cross pin 33. This cross pin extends through axial notches formed in the left end portion of the cylindrical part of the sleeve 36, and in the position of the sleeve 36 shown in Fig. 2 its left end abuts against a wall of the housing 31. The sleeve 36 is formed adjacent its right end, as viewed in Fig. 2, with an outwardly directed annular flange which terminates in a frustoconical portion extending toward the right side surface of the turning means 34, as viewed in Fig. 2. Thus, the turning means 34 and the flange of the control sleeve 36 define between themselves an annular groove, and a plurality of centrifugal elements in the form of ball members 37 are located in this annular groove. A ball cage 33 is lixed to the sleeve 3d and guides the ball members 37 for radial movement toward and away from the axis of the sleeve 36. The shaft 32 is formed at the left end of its hollow portion with a pair of diametrically opposed elongated slots 4d, and a cross pin 39 extends through these slots and is iixed at its ends to the sleeve 36 so that the latter is constrained to rotate with the shaft 32 but is axially shiftable with respect thereto.

A coil spring 42 is coiled about the shaft 32 at the right of the flange of the sleeve 36, and this spring 42 abuts with its left end, as viewed in Fig. 2, against this flange and urges the control sleeve 36 to the left, as viewed in Fig. 2, so that in the rest position of the parts which is illustrated in Fig. 2 the left end of the sleeve 36 will abut against a wall of the housing which rotatably supports the shaft 32 in the manner describedV above. The right end of the coil spring 42 abuts against another sleeve 45 which is connected to a cross pin 44 which extends through a pair of diametrically opposed slots 43 of the shaft 32 so that the sleeve 45 also is constrained to rotate with the shaft 32 but is axially shiftable with respect thereto, the diametrically opposed slots 43 of the shaft 32being aligned with a slot extending transversely through and axially along a shaft 52 located within the hollow shaft 32 and formed with a transverse bore through which the cross pin 33 extends so that the shaft 52 is constrained to rotate with the shaft 32 but is axially shiftable together with the control sleeve 36, the cross pin 44 extending through the slot of the shaft 52 in the manner shown in Fig. 2. The sleeve 45 is formed with an annular groove 46 which receives a sleeve-shifting pin 47 which is fixed to a lever 48 which is in turn fixed to a shaft 49 supported for rotation about its axis by the housing 31 and extending to the exterior of the housing where the shaft 49 is Vfixed to a lever Sti'which Ithrough a suitable linkage, cable, or the like is turnable by the operator to a predetermined angular position which will provide a preselected compression in the spring 42 upon turning of the lever 50.

The right end of the shaft S2, as viewed in Fig. 2, abuts against `the left free end of the shaft 21, as Viewed in Fig. 2, this shaft or bar 21 extending beyond the control means 8 and being connected to the lever 23 in the manner described above. The housing 32 threadedly carries an axially bored plug 53 through which the shaft 21 extends into the housing with its left free end portion slidably supported by the right interior end portion of the shaft 32. The shaft 21 has xedly connected thereto a collar 22 which abuts against one end of a spring 54 coiled about the shaft 2'1 and abutting with its right end against the plug 53 in the manner shown in Fig. 2 so that spring 54 urges the shaft 21 to the left, as viewed in Fig. 2.

The fuel conduit 7 is connected to the housing 31 by a threaded nipple member 55 fomied with openings through which the fuel of the conduit 7 flows to the cylinder 9 and extending into a threaded opening of the housing 31 so that the fuel from the conduit 7 also flows into the interior of the housing 31 through the connection 55. This nipple is in the form of a hollow tubular member which receives at its right end portion, as Viewed in Fig. 3, for slidable shifting movement a Valve member 56 which thus cooperates with the member 55 to form an overflow valve means which permits fuel from the conduit '7 to overflow into the return-How conduit 20 when a predetermined pressure is exceeded. It is apparent that the valve member 56 is acted upon by the pressure of the liquid which is in the cylinder 9 of the hydraulic moving means at the left face of the piston 10- therein, as viewed in Fig. 1, and if the valve member 56 is moved to the left, as viewed in Fig. 2, the pressure of this liquid in the hydraulic means 9, 10 will be increased so that the piston lil will be shifted to the right, as viewed in Fig. 1. The valve member 56 is provided at its right end, as viewed in Fig. 2, with an outwardly directed annular flange which abuts against the right end surface of the member 55 to close the interior thereof from the interior of the housing 31 when the valve member 56 is shifted to the left to its fully closed opsition, and just to the left of this ange the valve member 56 is formedy with an annular groove which cooperates with axial ribs formed in the outer surface of the valve member 56 so that in this way the fuel flows by the valve member 56 to'the return flow conduit 20 'when the valve member 56 1s 1n lts open position.

The left free end of the shaft 32 bears directly against the overflow valve member 56. In the position illustrated 1n Fig. 2 the valve member 56 is not under any load since the centrifugal ball members 37 between the 'turning means 34 and the control sleeve 36 have axial play and thus cannot transfer any axial pressure to the turning means 34 and from the latter to the shaft 32.

By turning the lever 50 to a predetermined angular position the compression of the spring 42 will be adjusted and the sleeve 36 will not move to the right under the centrifugal force of the ball members 37 until the centrifugal force is great enough to move the ball members 37 outwardly through a distance sucient to shift the sleeve 36 to the right against the force of the springv 42, and until such a centrifugal force is obtained the left end of the sleeve 36 engages the wall of the housing 31. During rotation of the shaft 32 the axial components of the centrifugal force which urges the ball members 37 outwardly away from the axis of the shaft 32, urges the sprocket wheel 34 to the left, as viewed in Fig. 2, and through the sprocket wheel 34, the cross pin 33, andthe shaft 32, all of which are constrained to move together axially, the valve member 56 is urged by the centrifugal force toward its closed position. Within the left hollow chamber of the housing 31 the fuel acts on the Valve member 56 with the pressure of the fuel in the reservoir 3. However, the pressure of the fuel in the conduit 7 acts on the other side of the valve member 56, this pressure in the fuel conduit 7 being derived from the pump 2. As long as the supply pump 2 supplies more fuel than is required by the injection pump 1, which is the rule during normal operation, then the overflow valve 56 is open and the excess fuel ows back through the return conduit 20 to the reservoir 3. In this manner the valve member 56 operates as an overflow valve, and the pressure required to open` the valve is determined by the axial components of the centrifugal force of the ball members 37 which act on the sprocket wheel 34.

The axial shifting of the valve member 56 will produce changes in the pressure of the fuel in the conduit 7 and these pressure changes will act on the piston 10 so as to move the latter and thus cause the lever 12 to shift the movable adjusting means 13. As a result of the threads of large pitch which interconnect the adjusting means 13 with the shafts 14 and 15 the angular position of the shafts with respect to each other is changed when the member 13 is axially shifted, the angular position of the shafts with respect to each other depending upon the axial position of the means 13, Inasmuch as the changes in the pressure of the fuel in the conduit 7 depend only upon the speed of rotation of the sprocket wheel 34 which rotates at a speed proportional to the speed of operation of the internal combustion engine, the angular turning of the shafts 14 and 15 with respect to each other will take place according to the same variable.

If the speed of rotation of the shaft 32 increases to anV extent which provides the axial components of the centrifugal force of the ball members 37 with a power great enough to overcome the force of the spring 42, then the ball members 37 move further away from the axis of the shaft 32 and shift the control sleeve 36 to the right,` while further compressing the spring 42. This movement of the control sleeve is transferred through the shaft 52 to the bar 21 and from the latter through the lever 23 to the rod 24 whose axial shifting changes the amount of fuel supplied by the injection pump to the engine, so that in this way the fuel supplied by the injection pump is lowered and a further increase in the speed of the engine is prevented.

Fig. 3 illustrates another embodiment of an overflow valve member which cooperates with the tubular nipple 55 and with the end of the shaft 32. In the embodiment of Fig. 3 the overflow valve member 58 is axially shiftable in the right end portion of the nipple screw 55 and is of a substantially cylindrical configuration. The end Vportion of the valve member 58 which extends outwardly to the right beyond the member 55, as viewed in Fig. 3, is provided with a stop 59 and in this way the areas at both sides of the valve member 58 which are respectively acted upon by the pressure of the fuel in the conduit 7 and the pressure of the fuel in the conduit are equal, so that the opening and closing pressures which respectively act to open and close the valve are of the same size. The valve is shifted through an axial distance until the fuel from the conduit 7 can flow out to the conduit 20 through the radial openings 60 which communicate with the axial bore of the valve member 58, these openings 60 being located behind the sealing ring of the valve member, and thus it is necessary for the valve member to move to the right, as viewed in Fig. 3, through a distance sufficient to uncover the openings 60 in order for the valve member to operate as an overflow valve.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of injection pumps differing from the types described above.

While the invention has been illustrated and described as Vembodied in adjusting devices for injection pumps, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt. it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. In a device for adjusting the timing of an injection pump, in combination, movable means for changing the timing of an injection pump upon movement of said movable means; hydraulic means operatively connected to said movable means for moving the same in response to changes in the pressure of a liquid in said hydraulic means; overflow valve means communicating with said hydraulic means and including a movable valve member which acts as an overflow valve member and which is movable for changing the pressure of the liquid in said hydraulic moving means so that upon movement of said valve member said movable means will be actuated by said hydraulic moving means; control means cooperating with said valve member for moving the same; and supply pump means for supplying the injection pump with fuel, said supply pump means communicating directly vand -at all times with said overflow valve means and hydraulic means for providing the latter with .the liquid whose pressure controls the movement of said movable means.

2. In la device for adjusting the timing of an injection pump, in combination, a shaft; support means supporting said shaft for rotation about its axis and for `axial movement along lits axis; a sleeve surrounding and slidably engaging said shaft and connected thereto for rotation therewith and `for axial movement with respect thereto, said sleeve having an outwardly directed annular flange; turning means surrounding said sleeve and connected operatively with said shaft for rotating the latter and said `sleeve therewith, said turning means being connected operatively to the engine which includes the injection pump to be rotated at a speed proportional to the speed of operation of the engine and said turning means having a side surface in a plane normal to the axis of said shaft and spaced from and directed toward said flange of said sleeve to define an annular space therewith, said flange having an outer portion defining part of a cone and extending toward said side surface of said turning means; a plurality of centrifugal members located in the space between said turning means and said flange and engaging said surface which forms part of a cone so that when the speed of rotation of said shaft, sleeve, and turning means is great enough the centrifugal members will engage said flange and side surface of said turning means to urge the same axially apart from each other and said turning means being laxially movable with said shaft so that the latter also moves axially; spring means acting on said sleeve for urging said flange thereof toward said` turning means; movable means for changing the timing of the injection pump upon movement of said movable means; hydraulic moving means operatively connected to said movable means for moving'the same in response to a change in the pressure of -a liquid in said hydraulic moving means; and overflow valve means communicating with said hydraulic moving means and including a movable valve member acted on by the liquid under pressure in said hydraulic moving means, said valve member engaging an end of said shaft and being moved upon axial movement of said shaft to change the pressure of the liquid in said hydraulic means so as to thereby move said movable means to adjust the timing of the injection pump.

3. in a device for adjusting the timing of an injection pump, in combination, a shaft; support means supporting said shaft for rotation about its axis and for axial movement along its axis; a sleeve surrounding and slidably engaging said shaft and connected thereto for rotation therewith land for axial mov-ement with respect thereto, said sleeve having an outwardly directed annular flange; turning means surounding said sleeve and connected operatively with said sha-ft for rotating the latter and said sleeve therewith, said turning means being connected operatively to the engine which includes the injection pump to be rotated at a speed proportional to the speed of operation of the engine and said turning means having a side surface in a piane normal to the axis of said shaft and spaced from and directed toward said iiange of said sleeve to dene an annular space therewith, said flange having an outer portion defining part of a cone and extending toward said side surface of said turning means; a plurality of centrifugal members located in the space between said turning means and said iiange and engaging said surface which forms part of -a cone so that when the speed of rotation of said shaft, sleeve, and iturning means is great enough the centrifugal members will engage said flange and side surface of said turning means to urge the same axially apart from each other and said turning means being axially movable with said shaft so that the latter also moves axially; spring means acting on said sleeve for urging said 4ilange thereof toward said turning means; movable means for changing the timing of the injection pump upon movement of said movable means; hydraulic moving means operatively connected to said movable means for moving the same in response to a change in the pressure of a liquid in said hydraulic moving means; overflow valve means communicating with said hydraulic moving means and including a movable valve member acted on by the liquid under pressure in said hydraulic moving means,-said valve member engaging an end of said shaft and being moved upon axial movement of said shaft to change the pressure of .the liquid in said hydraulic means so as to thereby move said movable means to adjust the timing of the injection pump; adjusting means operatively connected to said spring means for adjusting the force thereof so as to adjust the speed of rotation at which the centrifugal force of said centrifugal elementswill be great enough to axially shift said sleeve against the force of said spring means; and means responsive to axial movement of said sleeve for changing the amount of fuel supplied by the injection pump to the engine.

4. ln a device for adjusting the amount of fuel fed by and the timing of an injection pump for combustion engines, in combination, movable means for changing the timing of an injection pump upon movement of said movable means; hydraulic moving means operatively connected to said movable means for moving the same in response to changes in the pressure of a liquid in said hydraulic moving means; overflow valve means communicating with said hydraulic moving means and including a movable valve member acted on by the liquid under pressure in said hydraulic means so that said movable valve member may be moved to change the pressure ofthe liquid. and thus cause the hydraulic moving means to move said movable means; means for changing the amount of fuel supplied by the injection pump; and control means including a first member operatively connected to said means for changing the amount of fuel, a second member mounted for movement toward and away from said first member and engaging said valve member to move the same against the pressure of the liquid to change said pressure, spring means acting on said irst member and tending to move the same toward said second member, and centrifugal means operatively connected to said first and second members to move said members away from each other upon increase of the. engine speed.

5. In a device for adjusting the amount of fuel fed by and the timing of an injection pump for combustion engines, in combination, movable means for changing the timing of an injection pump upon movement of said movable means; hydraulic moving means operatively connected to said movable means for moving the same in response to changes in the pressure of a liquid in said hydraulic moving means; overiiow valve means communicating with said hydraulic moving means and including a movable valve member acted on by the liquid under pressure in said hydraulic means so that said movable valve member may be moved to change the pressure of the liquid and thus cause the hydraulic moving means to move said movable means; means for changing the amount of fuel supplied by the injection pump; and control means including a rst member operatively connected to said means for changing the amount of fuel, a second member mounted for movement toward and away from said first member and engaging said valve member to move the same against the pressure of the liquid to change said pressure, spring means acting on said first member and tending to move the same toward said second member, and centrifugal means located between and contacting said rst and second members for moving said members awayf from each other upon increase of the engine speed, said centrifugal means forming also a pressure transmitting member between said first and second members.

6. In a device for adjusting the amount of fuel fed by and the timing of an injection pump for combustion engines, in combination, movable means for changing the timing of an injection pump upon movement of said movable means; hydraulic moving means operatively connected to said movable means for moving the same in response to changes in the pressure of a liquid in said hydraulic moving means; overflow valve means communicating with said hydraulic moving means and including a movable valve member acted on by -the liquid under pressure in said hydraulic means so that said movable valve member may be moved to change the pressure of the liquid and thus cause the hydraulic moving means to move said movable means; means for changing the amount of fuel supplied by the injection pump; and control means including a first member operatively connected to said means for changingthe amount of fuel, a second member mounted for movement toward and away from said rst member and engaging said valve member to move the same against the pressure of the liquid to change said pressure, spring means acting on said first member and tending to move the same toward said second member, means for adjusting the tension of said spring means, and centrifugalmeans located between and contacting said first and second members for moving said members away from each other upon increase of the engine speed, said centrifugal Vmeans forming also a pressure transmitting member between said rst and second members.

References Cited in the file of this patent UNITED STATES PATENTS 2,305,308 Fischlmayr Dec. 15, 1942 

